A typical electric pencil sharpener comprises an electric motor, a gear train, a cutter assembly, and a receptacle for receiving a pencil or a pencil alignment device. The sharpener further comprises a switch for activating the motor, for example, upon insertion of a pencil. When the pencil is positioned in the receptacle, the motor transfers its power to the cutter assembly through the gear train. The pencil is sharpened by a blade of the cutter assembly. Numerous innovations for pencil sharpeners have been provided in the prior art that will be described.
Early designs of a conventional pencil sharpener typically comprise a spring-driven pencil sharpener comprising a top cap having a top opening to receive a pencil and two corresponding slots to receive a fastening device that includes two hollow frames. The pencil sharpener comprises a housing that is constructed with a pair of coupling castings, each of which is accompanied by a lateral cover for disposing a pencil blade set and a spring-driven automatic device. The outline of the housing is preferably designed to cooperate with that of the cap to form an egg-like shape that is comfortable to the hand and is attractive. However, the pencil to be sharpened in this typical sharpener is manually fed into the housing, which is inconvenient compared to an automatic pencil sharpener. In addition, the holding force for the pencil is provided by the user and is unstable, so the pencil sharpener is easily jammed and very noisy.
Another conventional pencil sharpener comprises a sharpening sub-assembly for sharpening pencils and first and second external shells having internal ribs defining surfaces for supporting the sharpening sub-assembly. The sharpening sub-assembly comprises an electric motor, a gear assembly, and a cutter assembly including a cutter gear module having an annular ring gear acting as a carrier support. The subassembly houses a pencil insertion switch and a receptacle presence switch. However, the holding force for the pencil is still provided by the user and is still unstable. The pencil sharpener is easily jammed and very noisy.
Another known automatic pencil sharpener comprises a motor, a transmission device, a cutter assembly, a feeding device, a feeding reverse mechanism, and a manual reverse mechanism. The feeding device has a pair of feeding rollers for feeding the pencil. The manual reverse mechanism for manually retreating the pencil has a pushing rod and a key switch. The pencil is fed by the feeding device and delivered to the cutter assembly. The cutter assembly processes the pencil. After the pencil is shaved, the feeding reverse mechanism drives the motor to rotate in a reverse direction so as to retreat the pencil from the sharpener. When the pencil is too short to shave and stops in the sharpener, the pencil is retreated from the sharpener by the manual reverse mechanism. This apparatus is very noisy also.
It is apparent that numerous innovations for pencil sharpeners have been provided in the prior art. Furthermore, even though these innovations may be suitable for the specific individual purposes to which they are addressed, the pencil is still manually fed with a holding force that is difficult to control such that jamming frequently occurs. Furthermore, the above prior art pencil sharpeners have not addressed the noise issue.
The products that are available in the market today do a fairly good job of sharpening pencils; however, they are annoyingly noisy. Many competitive exams and schools ban the use of electric pencil sharpeners during testing due to noise. The noise comes from grinding the sharpener's metal blade with the pencil's wood body. The older the electric pencil sharpener gets, the louder and less effective it becomes, resulting in pencils that have to be reinserted a number of times to make the lead pointed. Possibly the most annoying side effect is when the electric pencil sharpener keeps sharpening the pencil such that lead is exposed on only half of the side of the pencil and the other side of the pointed lead remains covered with material. The operator must continue to reinsert the pencil into the pencil sharpener in the hope that next time the lead may be fully exposed. This causes the pencil to become smaller and smaller each time.
In view of the foregoing, there is a need for improved techniques for providing an electric pencil sharpener that is quiet and effectively sharpens pencils without jamming.
Unless otherwise indicated illustrations in the figures are not necessarily drawn to scale.